Two men have a weight ratio of $5 : 3$. If the ratio of the time taken by them to climb stairs is $11 : 9$,find the ratio of their power.

$A$ force acts on a body of mass $15 \,kg$, initially at rest. If the instantaneous power due to the force at the end of the third second is $5 \,W$, then the instantaneous power (in $W$) at the end of the $4 \,s$ will be

An engine pumps water through a hose pipe. Water passes through the pipe and leaves it with a velocity of $2\, m/s$. The mass per unit length of water in the pipe is $100\, kg/m$. What is the power of the engine $?$ ................ $W$

The machine gun fires $240$ bullets per minute. If the mass of each bullet is $10 \ g$ and the velocity of the bullets is $600 \ ms^{-1}$, the power (in $kW$) of the gun is

$A$ particle moves with a velocity $\vec v = 6\hat i - 4\hat j + 3\hat k \, m/s$ under the influence of a constant force $\vec F = 20\hat i + 15\hat j - 5\hat k \, N$. The instantaneous power applied to the particle is ......... $J/s$.

$A$ body of mass $m$ is accelerated uniformly from rest to a speed $v$ in a time $T$. The instantaneous power delivered to the body as a function of time is given by